Administrative Supplements to Support Undergraduate Summer Research Experiences - Inhibition of Human Islet Amyloid Polypeptide Aggregation

摘要 胰岛淀粉样多肽的淀粉样聚集性与2型糖尿病β细胞死亡相关 (T2D)。IAPP是一种由β细胞与胰岛素共同分泌的多肽激素，是淀粉样蛋白中含量最高的蛋白质之一。 在体外很容易形成淀粉样纤维。越来越多的证据表明，抑制IAPP聚集和 聚集介导的细胞毒性是我们的长期目标，是一种有吸引力的预防β细胞的治疗策略 T2D中的死亡和阻止糖尿病病情的进展。随着冷冻-EM技术的最新进展， 结构生物学，已经解决了IAPP纤维的原子结构，由平行的对准β-Sheet组成 作为跨β的核心。然而，由于齐聚物中间体的异质性和瞬时性 在聚集过程中，从孤立的单体到最终的纤维的许多细节仍然未知。使用 淀粉样蛋白毒性可能通过与细胞膜的直接或间接相互作用而介导，它正日益增多。 这对于研究IAPP在膜环境中的聚集具有重要意义。越来越多的证据也表明 不同淀粉样变性疾病的病理相关性--例如，T2D是神经退行性变的危险因素 疾病，包括阿尔茨海默氏症和帕金森氏症；以及细菌淀粉样蛋白可能是导致发病的原因 神经退行性疾病和糖尿病。不同淀粉样蛋白之间的交叉相互作用 分子水平可能有助于相应疾病之间的病理相关性。我们有 证明了新型纳米颗粒可以被设计成减少hIAPP的聚集和细胞毒性。 尽管有许多优势，包括跨越生物障碍的能力，但纳米医学的主要问题 发展包括与免疫反应相关的潜在毒性和缺乏特异性。在这 Mira更新应用，PI建议继续揭示IAPP的分子机制 并探索抑制IAPP聚集和毒性的新的纳米颗粒方法。 以下方向：1)IAPP聚集和与膜的相互作用；2)相互作用 HIAPP和其他淀粉样变性蛋白；以及3)纳米粒缓解IAPP淀粉样变性 由内源性抑制物起作用。PI实验室将把计算建模和实验相结合 表征和验证。计算建模可以帮助弥合时间和长度尺度的差距 在实验观察和潜在的分子系统之间，不仅提供了分子 对实验观察的洞察力，但也提供了实验可验证的假说。这样的组合 计算和实验相结合的方法可以提高研究效率，缩短发现周期。这个 拟议研究的结果将有助于了解疾病机制和发现新的治疗方法 靶点(项目1)；为T2D和其他淀粉样蛋白之间的病理相关性提供分子基础 疾病，以及细菌感染和生物失调对T2D发病的贡献(项目2)； 设计具有高特异性和降低纳米毒性的抗淀粉样纳米颗粒的新方法(项目3)。 1

Abstract Amyloid aggregation of islet amyloid polypeptide (IAPP) is associated with β-cell death in type-2 diabetes (T2D). IAPP, a peptide hormone co-secreted with insulin by β-cells, is one of the most amyloidogenic proteins and readily forms amyloid fibrils in vitro. Mounting evidence suggests that inhibition of IAPP aggregation and aggregation-mediated cytotoxicity, our long-term goal, is an attractive therapeutic strategy to prevent β-cell death and stop the progression of diabetic conditions in T2D. With the recent advances of Cryo-EM in Structural Biology, atomic structures of IAPP fibrils have been solved, comprised of parallel in-register β-sheets as the cross-β core. However, due to heterogeneous and transient nature of oligomer intermediates populated during aggregation, many details of the process from isolated monomers to final fibrils are still unknown. With amyloid toxicity likely mediated by direct or indirect interactions with the cell membrane, it is increasingly important to study the aggregation of IAPP in the membrane environment. Increasing evidence also suggests pathological correlations between different amyloid diseases – e.g., T2D is the risk factor of neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases; and bacterial amyloids may contribute to the onset of neurodegenerative diseases and diabetes. Cross-interactions between different amyloid proteins at the molecular level might contribute to the pathological correlation between corresponding diseases. We have demonstrated that novel nanoparticles can be engineered to mitigate hIAPP aggregation and cytotoxicity. Despite many advantages including the ability to cross biological barriers, major concerns for nanomedicine development include potential toxicity associated with immune responses and the lack of specificity. In this MIRA renewal application, the PI proposes to continuously uncover molecular mechanisms of IAPP aggregation and to explore novel nanoparticle approaches to inhibit IAPP aggregation and toxicity in the following directions: 1) IAPP aggregation and interactions with the membrane; 2) cross-interactions between hIAPP and other amyloidogenic proteins; and 3) mitigation of IAPP amyloidosis with nanoparticles functionalized by endogenous inhibitors. The PI lab will combine computational modeling with experimental characterization and validation. Computational modeling can help bridge the time and length scale gaps between experimental observations and the underlying molecular systems, providing not only molecular insights to experimental observations but also offering experimentally-testable hypotheses. Such a combined computational and experimental approach can improve research efficiency and shorten discovery cycle. The outcome of the proposed studies will help understand disease mechanisms and discover novel therapeutic targets (Project 1); provide molecular bases for pathological correlations between T2D and other amyloid diseases, and the contribution of bacterial infections and dysbiosis to the onset of T2D (Project 2); and offer new approaches to design anti-amyloid nanoparticles with high specificity and reduced nanotoxicity (Project 3). 1